Method of manufacturing spiral drilling bits and the like



Nov. 16,1926. v 1,607,089

. F. H. LElDEcKER G SPIRAL DRILLING BITS AND THE LIKE Filed 001:. 27. 1925 Patented Nov. 16, 1926 rosrnn H; LEIDECKEB, or MABIETTA, onto, Assmnon TO THE nnrnncnnn TOOL 00.,

, or M RIETTA, OHIO. I

' idETI-IOD OF MANUFACTURING'SPIRAL DRILLING BITS AND THE LIKE.

Application filed October 27, 1.925. Serial No. 65,198.

This-invention relates to method of ma ing spiral drilling bits and like devices such bit or the like each rib or wlng of which will be kept in proper shape during the twisting operation and not become, distorted when elongated by a twisting operation.

Withthe foregoing and other objects in view the invention consists in certain novel steps in the method of producing spiral drilling bits and the like, which will be hereinafter more fully described and pointed out w in the claims, it being understood that various changes may be madewithout departing I from the spirit of the invention as claimed. In the accompanying drawings I have shown some dies used in carrying out the method and have also shown thearticle duced. p

In said drawings,

Figure 1 is a perspective view of a forging die by means of which the billet is given its 7 initial'shape prior to the twisting operation. v

reption of the shaped billet received from Figure 2 is a perspective view of the twisting die, the position of the billet therein being indicated by broken lines.1

Figure 3 is aperspective view of one of.

the members of the twisting die.

Figure 4 is a transverse section through the billet as it appears after the forging operation.

spiral drilling bits or the like produced by the action of the twisting die.

Figure 6 is an elevation of a po-rtionof the billet after being acted on by the forging dies.

Figure 7 is a similar View showing the partially formed spiral ribs or wings produced by the twisting dies.

Figure 8 1s a viewof a portion of com pleted spiral drilling bit.

For the purpose of carrying out the method constituting the present invention there are provided two sets of dies. One set of these dies is used for forging the stock to shape prior to the twisting operation while the dies of the other pair are employed for imparting a twist to the wings or ribs of the P tween and cl 1n said figure. The reason for tool, These twosets of dies can be actuated simultaneously in a single machine or in separate machines, or 1f preferred, can be separately operated. The forging dies have been illustrated inFigure 1 and consist of the cooperating members 1' and 2 the meeting faces of which are recessed as at 8 to provide oppositely extendlng lateral spaces 4 separated by superposed oppositely extending recess extending into the dies. The end walls of the recesses 5 are preferablyv concaved transversely asv shown at 6 while the sidewalls of these recesses diverge toward the spaces't and merge, along rounded shoulders 7, into the walls of said spaces. The diverging walls of the recesses 5 have been indicated at 8 while those walls of the spaces 4L- extending from the rounded shoulders 7 have been indicated at 9. These walls 9 diverge from the recesses 5 and terminate at the end walls 10 which converge to the meeting faces of the dies land 2 where they come together. In practice the distance from a to b in Figure 1 is equal to the distance bethis will be hereinafter explained.

The twisting dies have been indicated at 10 and 11 in Figure 2 and are provided with recesses 12 in theirmeeting faces for the rethe dies 1 and 2. In each of the recesses 12 V is formed a tapered obliquely disposed fuller l3 designed to enter between the wings 'or ribs of the formedbillet and impart a. spiral twist thereto. V The billet'to be formed into a spiral drill- V I V .ing bit or the like is placedbetween and Figure '5 is a similar, View showing thev shaped by the dies 1 and 2 and will be given the cross sectional contour outlined by the walls of the several recesses within said dies. Thereafter the billet is given a one-quarter turn and again subjected to the action of I the dies. By this last operation those wings or ribs of the billet previously formed within the spaces 4: will have their longitudinal edge portions rounded by the concave end walls 6 of the recesses 5 while the sides of ed outer faces 14 and inwardly converging side walls 15. The core 16 of the billet thus formed will be over-size. By now placing the billet between and subjecting them to the action of-the dies 10 and 11, the opposed fullers 13 will impart twists to two of the wings and, during this twisting operation,

will displace some of the metal of the core 16 so that it will flow into the Wings being twisted and compensate for the stretch which results from the elongation thereof due to twisting Thus the wings will not become distorted but wil-l'mainta-in their cross sectional cont-our. thus been given a twist for a portionof their length the billet is rotated through onefourth of a circle and again subjected to the action of the dies 10 and 11. The remaining two wings will thus be twisted and metal displaced from the core into them to preserve the cross sectional contours of the wings. Thereafter the billet is fed forwardly step by step between the dies and the foregoing operation repeated until the wings have been twisted throughout their lengths. The displacement of metal from the core into the wings will of course reduce the size of the core so that the cross sectional cont-our of the tool will be changed from that illustrated in Figure 4 to approximately the contour shown in Figure 5. In this figure as well as in Figures 6, 7 and 8, the wings have been illustrated at 17 Figure 6 shows a portion of the billet after it has been forged to the shape shown in Figure & while Figure 7 as heretofore explained, shows the billet partly twisted after it has been acted on one or more times by the dies 10 and 11. A portion of the completed tool has been illus trated in Figure 8; The particular configuration of the spiral drilling bit has certain advantages over other forms of tools of this type but as this particular drilling bit or the like constitutes no part of the present invention it is not deemed necessary to point out the advantages at this time. The great est objection to producing a drilling bit having the cross sectional contour herein disclosed has been in the diflioulty in produc- After two of the wings have ing the tools by a forging method. By providing dies such as described and using them in the manner set forth tools of this= oharacter having wings of special cross sectional. contours can be produced readily by forging and, because of the displacement of metal into the wings during the twisting operation, said wings or ribs will maintain their contours even though elongated when twisted.

What is claimed is': v

1. The herein described method of producing spiral drilling bits and the like whichconsists in forging a billet to produce wings of predetermined cross sectional contour and an over-size core, and thereafter sii'nultaneo'usly twisting the wings and forcing the'reinto surplus metal from the core to compensate for elongation of the wings due to twisting. V

2. The, herein described method of producing spiral drilling bits a'nd the like which includes forging a billet to produce wings having substantially'the cross sectional contour of the wings of the finished tool, the core of the billet being over-size, and thereafter subjecting the billet -to the action of twisting dies for imparting a twist to the wings and reducing the size of the core, the

surplusmetal of the core being directedinto the wings to compensate for elongation of the wings due to twisting, thereby to main tain the predetermined cross sectional contour of the wings.

8. The herein described method of producing spiral drilling bits and'the like which consists in'producing a billet having an oversize core and radial Wings, and thereafter feeding 1 the billet intermittently between twisting dies, said dies operating to' simultaneously twist the wings of the billet and displace surplus metal from the oversize core into the wings, thereby to compensate for the elongation of the wings due to twisting.

In testimonythat I claim the foregoing as my own, I have hereto affixed my signature.

FOSTER H. LEIDE'CK'ER. 

